Kagama Hobbywing Max 8 overheating on 4s

[Trucking in space]

First a big thanks to everyone who helped me set me roller up with correct parts.
My previous RC experience has all been on 3 and 4s. I have an Arrma Felony which I've only ever run on 4s, and a Granite 3s.
Never had an issue with their ESCs, even though the Felony has a version 1 Firma 150 amp ESC, that apparently doesn't handle 6s well.
With my temp gun, 130 Fahrenheit is the worst I've seen, and never had an overheat "shut down"
Today was 91 degrees when I ran my Kagama on 4s for the 3rd time.
Within 5 minutes (timestamp on the screenshots) of running with a throttle dual rate set at 75% but never hitting full trigger, my ESC shut down with blinking single red light.
I had driven the truck 15 minutes to the place I run at, but drove it at 5 mph max.
Temperature was 131 at 6:05 and 181 at 6:10
ESC fan is operating fine. Am I expecting too much of this ESC running in 90 degree weather? I never expected to thermal shutdown on 4s in 5 minutes. Anyone else run Max 8 ESC in hot weather wanna chime in ? Does the stock fan suck? Do I need an aftermarket fan ? I use a 40mm 12 volt 1 amp server fan on my motor, and it only gets a little hot.
I didn't expect the Max 8 to be such a p***y ESC. My bad ? I bought it from Amain Hobbies, so I don't think I can just return it and buy a Max 6 instead. I shoulda stuck with Amazon...
Any advice would be great. Thanks in advance!

 

[Horatio]

I can't comment on the Max 8, not really, although the Torox 185 is similar.

The Kagama is a much heavier rig than your Felony, so the load on Motor/ESC is going to be greater.

Lower speed running, with on/off on the throttle tends to be more demanding on both ESC and the motor, much like racing on a tight twisty indoor track, although I note that it's your ESC with the heat. Your motor seems cool enough.

But it's where the rig is accelerating hardest from stationary or low speed (or anywhere closer to the stall current shown on the graph) that draws the most current. At maximum speed or cruising at a fixed speed will draw less, even at full throttle. This is counter-intuitive, but motors produce maximum torque from stationary.

You'll note that maximum efficiency is achieved around 30% of maximum power. Maximum power (torque multiplied by revs) is right in the middle of your rev range, before torque falls away as the RPMs rise.

My motor hit this temp the last time I went out:

And this was with dual fans and at around 70° weather, running on 6S with 4292 1780KV. But I was punching full throttle, using 19/52 gearing hitting 69 mph. It's hard on batteries and motor. My ESC was fine though.

It was close to shutting down, but I gave it a 5 minutes of cooling off.

The Max 8 is very highly regarded, so I'm sure there are people here who can be more specific. On 6S and around 5200mah, I generally get around 6-8 mins of useful high speed run time - then the last couple of minutes goes soft before LVC, where my batteries show 0% on the charger.

This is where all the petrol heads chime in....

 

[Nelson.81]

First a big thanks to everyone who helped me set me roller up with correct parts.
My previous RC experience has all been on 3 and 4s. I have an Arrma Felony which I've only ever run on 4s, and a Granite 3s.
Never had an issue with their ESCs, even though the Felony has a version 1 Firma 150 amp ESC, that apparently doesn't handle 6s well.
With my temp gun, 130 Fahrenheit is the worst I've seen, and never had an overheat "shut down"
Today was 91 degrees when I ran my Kagama on 4s for the 3rd time.
Within 5 minutes (timestamp on the screenshots) of running with a throttle dual rate set at 75% but never hitting full trigger, my ESC shut down with blinking single red light.
I had driven the truck 15 minutes to the place I run at, but drove it at 5 mph max.
Temperature was 131 at 6:05 and 181 at 6:10
ESC fan is operating fine. Am I expecting too much of this ESC running in 90 degree weather? I never expected to thermal shutdown on 4s in 5 minutes. Anyone else run Max 8 ESC in hot weather wanna chime in ? Does the stock fan suck? Do I need an aftermarket fan ? I use a 40mm 12 volt 1 amp server fan on my motor, and it only gets a little hot.
I didn't expect the Max 8 to be such a p***y ESC. My bad ? I bought it from Amain Hobbies, so I don't think I can just return it and buy a Max 6 instead. I shoulda stuck with Amazon...
Any advice would be great. Thanks in advance!

View attachment 6779

View attachment 6780

I’ve heard of people having heating issues with kagama on 6s but not 4s, something not right somewhere, what size motor/kv & pinion you running.

 

[Mark383]

First a big thanks to everyone who helped me set me roller up with correct parts.
My previous RC experience has all been on 3 and 4s. I have an Arrma Felony which I've only ever run on 4s, and a Granite 3s.
Never had an issue with their ESCs, even though the Felony has a version 1 Firma 150 amp ESC, that apparently doesn't handle 6s well.
With my temp gun, 130 Fahrenheit is the worst I've seen, and never had an overheat "shut down"
Today was 91 degrees when I ran my Kagama on 4s for the 3rd time.
Within 5 minutes (timestamp on the screenshots) of running with a throttle dual rate set at 75% but never hitting full trigger, my ESC shut down with blinking single red light.
I had driven the truck 15 minutes to the place I run at, but drove it at 5 mph max.
Temperature was 131 at 6:05 and 181 at 6:10
ESC fan is operating fine. Am I expecting too much of this ESC running in 90 degree weather? I never expected to thermal shutdown on 4s in 5 minutes. Anyone else run Max 8 ESC in hot weather wanna chime in ? Does the stock fan suck? Do I need an aftermarket fan ? I use a 40mm 12 volt 1 amp server fan on my motor, and it only gets a little hot.
I didn't expect the Max 8 to be such a p***y ESC. My bad ? I bought it from Amain Hobbies, so I don't think I can just return it and buy a Max 6 instead. I shoulda stuck with Amazon...
Any advice would be great. Thanks in advance!

View attachment 6779

View attachment 6780

Hi mate,

I've got A Max 8 combo in my V1 EXB KRATON which I only ever use on 4S and the only time the ESC got hot was when the fan failed on it and once when driving on a super hot day in a tight dusty parking lot where I was only using part throttle and that's in 2 and a half years of driving.. ..
Horatio's legendary reply to you says it all and was what I found after doing research about part throttle driving that it is more stress on the esc causing me heat..
One thing I was wondering is what pinion are you running? I run 15 tooth on my Max 8 and anymore on a big truck like mine would be really pushing it especially in a hot climate like Australia where I am. As one reply said the KAGAMA is a portly girl so if you do have a larger pinion that very well could be the cause.
Cheers

 

[Sandracer_NL]

Ambient temperature definitely has a significant impact on electronics temperatures. But 90F and slow running can not lead to thermal shutdown.
I ran the Muraco in 27C (81F) yesterday and with no breeze and on the sand it felt like warmer. I was not easy on throttle, and although I did not measure esc temp, the motor was 58C (136F) and no thermal. Everything stock, except for a 40mm 12v fan running on 6v (receiver).
The Kagama weighs more (+1KG) and has bigger tires, which both are heavier on electronics causing heat. But even that can not lead to thermal with slow driving as you mentioned.
Normally I would say you have binding somewhere (often poop bearings in diffs or motor), but since in this case I’m wondering if your gearing (pinion/spur) is too high with a thick center diff fluid. That combination (with larger tires) gave me the same result a few years ago and also destroyed a lipo (three cells were above 4v, but one cell dropped well below 3v).
You said you were running crawling speed, did you notice cogging?

 

[Trucking in space]

I’ve heard of people having heating issues with kagama on 6s but not 4s, something not right somewhere, what size motor/kv & pinion you running.

Stock 13t pinion
4278 sensored 2250kv
It's the motor that came with the Max 8 G2S combo pack.
I did a little better tonight, only one thermal shutdown at the end of my run.
I run on dirt \ loose gravel.
I put a second 30mm fan on the ESC, above the stock one.
I ordered a 40mm 12v 1 amp server fan (same as on the motor) to put on the ESC.
I'm thinking about contacting Hobbywing.
I'm also wondering if Kagama is too heavy for the max 8.
I use a 9000 mAh 80c 4s Zeee soft pack, which is a heavy-ish battery.

Ambient temperature definitely has a significant impact on electronics temperatures. But 90F and slow running can not lead to thermal shutdown.
I ran the Muraco in 27C (81F) yesterday and with no breeze and on the sand it felt like warmer. I was not easy on throttle, and although I did not measure esc temp, the motor was 58C (136F) and no thermal. Everything stock, except for a 40mm 12v fan running on 6v (receiver).
The Kagama weighs more (+1KG) and has bigger tires, which both are heavier on electronics causing heat. But even that can not lead to thermal with slow driving as you mentioned.
Normally I would say you have binding somewhere (often poop bearings in diffs or motor), but since in this case I’m wondering if your gearing (pinion/spur) is too high with a thick center diff fluid. That combination (with larger tires) gave me the same result a few years ago and also destroyed a lipo (three cells were above 4v, but one cell dropped well below 3v).
You said you were running crawling speed, did you notice cogging?

I was doing crawling speed for 15 minutes to get to my driving spot (my doctor says I need to walk more ) and after that I drove around the track (dirt and gravel) at around 50%75% throttle, with the throttle dual rates set to 75%
I have the stock 13t pinion and factory oil in all the diffs, stock tires.
I run a large 9000 mAh 4s soft pack.
No cogging, as the motor is sensored.
The gear mesh is okay, possibly a little loose if anything.
Thanks for the input.

 

[Nelson.81]

Stock 13t pinion
4278 sensored 2250kv
It's the motor that came with the Max 8 G2S combo pack.
I did a little better tonight, only one thermal shutdown at the end of my run.
I run on dirt \ loose gravel.
I put a second 30mm fan on the ESC, above the stock one.
I ordered a 40mm 12v 1 amp server fan (same as on the motor) to put on the ESC.
I'm thinking about contacting Hobbywing.
I'm also wondering if Kagama is too heavy for the max 8.
I use a 9000 mAh 80c 4s Zeee soft pack, which is a heavy-ish battery.

I don’t like those new frameless fans on new max8 esc, mine broke screws holding was just bouncing about inside. Still think it shouldn’t be overheating so much but I live in a cooler climate (N.Ireland). Some run max8 in kagama but if having issues with it in buggy just go max6, a lot do on the heavier rigs, I’ve max6 to drop in my Kronos build.

 

[Trucking in space]

I just thought of something. I'm using an xt90 to EC5 adapter.
Could the adapter be causing more amp draw from the ESC?
All my batteries are EC5, and I didn't want to void my Hobbywing warranty by cutting off the xt90.
I always hear people (in videos) say not to use an adapter, but none of them say why not to use one.
Possibly this is just my inexperience. I've never had to run adapters before.
¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯

 

[Niekname]

Adapters add resistance, the higher the resistance, the more energy is lost and turned into heat. So basically your battery c rate is lower. The ESC then has less power to work with, and does produce more heat. Think of it like your fuel line to your engine, but it is just to small to let all the fuel the engine wants trough. You are starving it from energy.

This could be a part of the problem, but still I wouldn't think you would overheat on 4s, especially not the ESC. Have you verified the fan is spinning and hasn't lost any blades?

Also EC5 fits into XT90, just a little bit looser then most connections and with slightly more resistance, so you could try that out to verify if the adapter is the problem. Also have you tried different batteries? If your battery is old it can also have more internal resistance, which also leads to lower c rating.

And do you run your BEC at 6v or 7.4? Do you have aftermarket servo or other things connected to BEC?

 

[Horatio]

I just thought of something. I'm using an xt90 to EC5 adapter.
Could the adapter be causing more amp draw from the ESC?
All my batteries are EC5, and I didn't want to void my Hobbywing warranty by cutting off the xt90.
I always hear people (in videos) say not to use an adapter, but none of them say why not to use one.
Possibly this is just my inexperience. I've never had to run adapters before.
¯⁠\⁠_⁠(⁠ツ⁠)⁠_⁠/⁠¯

"The XT90 connector excels in high-current applications and can handle currents up to 90A. On the other hand, EC5 connectors can typically handle currents up to 60A"

 

[Trucking in space]

Adapters add resistance, the higher the resistance, the more energy is lost and turned into heat. So basically your battery c rate is lower. The ESC then has less power to work with, and does produce more heat. Think of it like your fuel line to your engine, but it is just to small to let all the fuel the engine wants trough. You are starving it from energy.

This could be a part of the problem, but still I wouldn't think you would overheat on 4s, especially not the ESC. Have you verified the fan is spinning and hasn't lost any blades?

Also EC5 fits into XT90, just a little bit looser then most connections and with slightly more resistance, so you could try that out to verify if the adapter is the problem. Also have you tried different batteries? If your battery is old it can also have more internal resistance, which also leads to lower c rating.

And do you run your BEC at 6v or 7.4? Do you have aftermarket servo or other things connected to BEC?

Thanks for all the input.
I haven't tried plugging the EC5 into the xt90 yet. I thought that maybe the problem would be worse, as the connection is much less snug.
I imagine if I run on the 3s battery, the heat problem would be less, as less amps overall.
Today I went to an 11 tooth pinion and my temps maxed out at 160-something after 20 minutes. My ESC fan is running fine. Stupid G2S has feature where the fan only runs when temperature is elevated. I put a second fan on top of ESC fan, same size, it runs all the time.
My motor fan is a bit of a load, as it's 1 amp

7.4 v BEC
Yipin (GxServo) servo
I run a small LED headlight.
The first 2 times I overheated, I was not running the LED.
I only have one 4s battery. The other two are 3s. The 4s battery is maybe 6 months old Zeee battery.

I hope I covered everything, and thank you everyone for helping me out. I'm still new to the hobby and this is my first roller build.

I notice that my amp draw has been as high as 120 amps. Why would the Max 8 come with a connector type of xt90 if the amp draw is higher ?
I also see two different statistics for EC5 connectors amp rating. One source says 60 amps, the other (cellsaviors.com) says 120 amps.
I ordered an ec5 bullet set and plastic connector "sheath" to solder onto my Max 8 directly. Is this a bad idea?
From what I've seen on ArrmaForums.com, Hobbywing will not be likely to give me warranty service regardless of whether I chop the xt90 off or not. They're apparently b*st*rds when it comes to warranty replacement (citation needed).
If EC5 does max out at 60 amps, then my idea is bad. I don't feel comfortable soldering battery leads, so I may just buy a new CNHL 5s battery with an xt90 plug, to test the adapter theory.

Big thanks to everyone helping me with this issue. I'm a FNG when it comes to RC (this is my 3rd RC of hobby grade and my first roller build. I'm still a greenhorn with wet ears, and maybe I'll say dumb things sometimes or not understand the issue properly.
Thanks for your patience!

 

[Trucking in space]

I'm an idiot. I assumed I was getting an ESC thermal cutoff because the truggy completely stopped moving, only the steering servo functioned.
But I had the red light on the ESC doing a single flash, which the manual says is LVC state.
I am open to the possibility that my Zeee "80C" battery is a lying can of feces, and my ESC has decided I was at LVC because the Zeee battery cannot provide enough amps due to a low C rating, regardless of what the specifications say.
However, I am very puzzled, because in all my other vehicles, when I hit LVC naturally, there is no throttle cut, but the vehicle goes instead very slowly, to indicate LVC
So now I am confused, because I do have high temperatures (high maximum temperature according to the HW app), but the instructions say flashing red light is LVC warning.
I just have never had full throttle cutoff on LVC, not on a hobby grade vehicle. I've seen toy RCs do LVC like that, with no throttle response after LVC.
Sorry I am so confused and confusing with my unreliable information.
It would be a huge help if anyone else owning the Max 8 G2S (sensored) ESC can please let me know if their LVC results in complete throttle cut ?
Thank you everyone again in advance.
I am not trying to make this process difficult, but my small amount of experience is causing me to be confused about the situation.

Everyone here has been a very good help and I appreciate the patience in dealing with my poor skill level and confusing contradictions.

 

[Nelson.81]

Your right you should feel a dip in power before lvc cuts in though sometimes, I don’t notice happening myself depending on driving situation or sometimes can only a few secs notice before it dies completely, sign you’ve hit lvc and not thermal is fact you still got steering that is the norm. Normally on 6s with 5500 mah 60c gens/ace Lipo Batteries I’m looking at 10/15mins max run time with my buggy, on a bigger rig would expect a bit less runtime.

 

[Sandracer_NL]

I had the same thing once. The esc almost immediately went into LVC. After checking the voltage on the lipo 3 cells still had a near full voltage (around 4v), but one cell was below 3v. I got rid of that lipo off course.
Apart from checking the voltage, you can also check internal resistance of the lipo, which is a better indication of the lipo’s health.

 

[Horatio]

Lipos 'dump' rapidly. But for a few seconds before the LVC, you'll note they go soft. Ie - less acceleration and top speed.

 

[The Stig]

Lipos 'dump' rapidly. But for a few seconds before the LVC, you'll note they go soft. Ie - less acceleration and top speed.

That is a fact. When this happens get the car back. Otherwise it is a long walk Always take good care of your lipos. Check the voltage regularly and always balance charge. And storage when not driving for a long time. Read a lot of c r a p about the Zeee batteries. Wanted to give them a go also. But did not after reading reviews. I have turnigy hardcase 4s lipos and the CNHL 3s softcase lipos. Put to of the 3s together and i was impressed om 6s. Lost a CVD after that on my Asuga Will buy more CNHL lipos in the future.

 

[Horatio]

That is a fact. When this happens get the car back. Otherwise it is a long walk Always take good care of your lipos. Check the voltage regularly and always balance charge. And storage when not driving for a long time. Read a lot of c r a p about the Zeee batteries. Wanted to give them a go also. But did not after reading reviews. I have turnigy hardcase 4s lipos and the CNHL 3s softcase lipos. Put to of the 3s together and i was impressed om 6s. Lost a CVD after that on my Asuga Will buy more CNHL lipos in the future.

I've always been impressed with my 4S and 6S CNHL lipos with my FPV drones. I've got around 8 of them, including some HV versions. They're great and not that expensive.

 

[Trucking in space]

Okay, the end of the story has occured.
I appreciate everyone's input, and before I go further, I have to ask everyone to please excuse my lack of experience.
Today when I was out, I tried a 6v BEC, and I didn't run into the cutoff issue on the 4s battery.
However, my "drive back home" battery (I live 15 minutes from my bash spot and walk there) is a cheap AF Hoovo "50C" pack, and I hit a shut down 2 times. The second time was right after doing a bunch of jumps for some neighbor kids. This time when it shut down, I noticed my "lowest voltage" reading was 7.3 volts, on a 3s battery, remember.
So, my lipos are to blame, they're only 6 months old, but clearly not 50c and not suitable for Kagama use.
Buy cheap, buy twice, I guess. The voltage remained so low on that 3s battery that when I turned the ESC back on, it just beeped at me continuously, and wouldn't drive. That's when I checked the voltage.
So I wasted everyone's time by not fully understanding LVC.
I apologize, and I have ordered a quality 5s true 40c battery from CNHL.
Again, really sorry for misunderstanding the situation and wasting y'all's brainpower and typing effort \ time.
I guess my voltage was so low that a protection cutoff had been reached.
Now I understand why people pay extra for big brand batteries.

"The XT90 connector excels in high-current applications and can handle currents up to 90A. On the other hand, EC5 connectors can typically handle currents up to 60A"

I'll stick with the XT90 then. Ordered a CNHL 5s 40C with an XT90.

 

[Horatio]

Okay, the end of the story has occured.
I appreciate everyone's input, and before I go further, I have to ask everyone to please excuse my lack of experience.
Today when I was out, I tried a 6v BEC, and I didn't run into the cutoff issue on the 4s battery.
However, my "drive back home" battery (I live 15 minutes from my bash spot and walk there) is a cheap AF Hoovo "50C" pack, and I hit a shut down 2 times. The second time was right after doing a bunch of jumps for some neighbor kids. This time when it shut down, I noticed my "lowest voltage" reading was 7.3 volts, on a 3s battery, remember.
So, my lipos are to blame, they're only 6 months old, but clearly not 50c and not suitable for Kagama use.
Buy cheap, buy twice, I guess. The voltage remained so low on that 3s battery that when I turned the ESC back on, it just beeped at me continuously, and wouldn't drive. That's when I checked the voltage.
So I wasted everyone's time by not fully understanding LVC.
I apologize, and I have ordered a quality 5s true 40c battery from CNHL.
Again, really sorry for misunderstanding the situation and wasting y'all's brainpower and typing effort \ time.
I guess my voltage was so low that a protection cutoff had been reached.
Now I understand why people pay extra for big brand batteries.

View attachment 6870


I'll stick with the XT90 then. Ordered a CNHL 5s 40C with an XT90.

Just out of interest - how is the ESC when it comes to dealing with 5s? The Torox ESC isn't really able to deal with them. It can 4s or 6s, but there's no option for detecting 5s.

 

[AngrySection8]

Just out of interest - how is the ESC when it comes to dealing with 5s? The Torox ESC isn't really able to deal with them. It can 4s or 6s, but there's no option for detecting 5s.

He's got a g2, it won't auto detect 5s I don't believe but will allow to be manually set it to 5s